Fuel supply system



Oct. 17, 1961 s. M. UDALE FUEL SUPPLY SYSTEM Filed March 16. 1959 I N VEN TUR.

3,004,531 FUEL SUPPLY SYSTEM Stanley M. Udala, Detroit, Mich., assignor to Holley Carburetor Company, Van Dyke, Mich., a corporation of Michigan Filed Mar. 16, 1959, Ser. No. 799,747 13 Claims. (Cl. 12S-140) The present invention relates generally to a fuel supply system for an internal combustion engine, and more particularly to a fuel injection system including means responsive to deceleration of an engine to shut off fuel supply thereto.

The present application is a continuation-impart of my prior copending application Serial No. 703,934, filed December 19, `1957, now Patent 2,900,969, issued August 25, 1959.

It is an object of the present invention to provide a fuel supply system including a fuel delivery pump, and means responsive to deceleration of the engine for cutting off delivery of fuel.

It is a further object of the present invention to provide a fuel supply system for an internal combustion engine including means responsive to manifold vacuum, as modified by venturi vacuum, for regulating the supply of fuel to the engine, and means responsive to deceleration of the engine for cutting olf the supply of fuel thereto.

It is a further object of the present invention to provide a fuel supply system for an internal combustion engine including means responsive to manifold vacuum for regulating the supply of fuel to the engine, and means responsive to attainment of a manifold vacuum corresponding to deceleration of the engine for cutting off the supply of fuel thereto.

ilit is a further object of the present invention to provide a fuel delivery system for an internal combustion engine having a manifold, a supply passage connected to said manifold, and a supply valve in said supply passage, said fuel delivery system including a fuel delivery pump, means responsive to engine manifold vacuum for regulating said pump, and a shut-od valve responsive to engine deceleration and effective to cut off fuel delivery by said pump during engine deceleration.

It is a further object of the present invention to provide a fuel delivery system as described in the preceding paragraph in which the shut-off valve has vacuum operated motor means connected thereto, a passage connecting said motor means to enginemanifold vacuum, and a control valve in said passage responsive to engine manifold vacuum and operable to open said control valve only upon attainment of engine manifold vacuum corresponding to engine deceleration with closed throttle.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing, illustrating a preferred embodiment of the invention, wherein:

The figure is a schematic elevational view of the systern with parts in section.

In the figure there is illustrated a fuel pump 1t) having a drive shaft 12 connected thereto and adapted to be driven from a rotating part of an internal combustion engine, such for example as the cam shaft 14 thereof, the interconnection between the shafts 12 and 14 being indicated by gearing 16. The pump is of a known type and has means for adjusting the fuel delivery per revolution thereof. A pump of this type is disclosed in British Patent 414,954 of August 16, 1934, to which reference is made for details of a pump having the statedfunction. Accordingly, the details of the pump will not be described herein. `It is sufficient to note however,

ffatented Oct. 17, 1961 that adjustment of the output or delivery of fuel per revolution of the shaft l2 is accomplished by an adjusting member herein illustrated as a rack 18 movable longitudinally and engageable with a pinion 19 carried by the pump. Movement of the rack l to the right, as seen in the figure, results in an increase of fuel delivery per revolution of the shaft, and movement of the rack to the left results in a reduction in the fuel delivery per revolution of the shaft. At this time it may be noted that since the pump is operated at a speed dependent on engine speed, fuel delivery is thus automatically proportioned to engine speed and thus tends generally to be properly related to the quantity of air drawn into the cylinders of the engine. However, under different operating conditions the fuel-air ratio requires modification and the system now to be described effects a control thereof adapted to produce a smooth engine performance curve.

The air intake comprises a generally tubular body 20 mounted on the engine intake manifold 22. The body 2h has an air passage 24 formed therein shaped to provide a venturi 26 intermediate its ends. Disposed above or upstream from the venturi 26 is a throttle valve 28 mounted on a shaft 30.

it will be understood that during engine operation when the air control valve 28 is in partially closed position, a pressure drop occurs across the valve 2S and the pressure below the valve assumes or is substantially equal to manifold pressure. Flow of air through the venturi however, causes pressure within the throat of the venturi to be depressed below the approximately equal values of manifold vacuum existing above and below the venturi. Pressure above the valve 28 is approximately atmospheric or may be slightly reduced therefrom by passage of the air through an air cleaner or the like.

,ln order to effect automatic adjustment of the fuel pump l@ the rack 18 is connected to a exible diaphragm 32 mounted within a housing formed by portions 34 and 36 between which the edges of the flexible diaphragm are clamped. To the right of the diaphragm as seen in the figure, there is thus provided a chamber 38 which communicates with atmosphere through a port 40. To the left of the diaphragm 32 there is provided a chamber 42 containing a compression spring 44 urging the flexible diaphragm 32 to the right as seen in the figure. The chamber 42 communicates through conduit 46 with a plurality of sources of reduced pressure or vacuum as will now bedescribed.

Located at the throat of the venturi 26 is a restricted port 48 communicating with an enlarged passage 50 leading to a chamber 52 which is in communication with the conduit 46. Located at the inner surface of the passage 24 in a position to be traversed by an edge of the 4valve 28 as it moves into and out of fully closed position are a pair of ports54 and 56 which communicate with a passage 58 leading to the previously described passage 50. It will be observed that the ports 54 and 56 both lie upstream from the Valve 28 when it occupies its fully closed position, as illustrated in dotted lines. However, when the `air valve is given limited opening movement its adjacent edge traverses the ports 54 and 56 and transfers these ports to the downstream side of the 4air passage where they then afford a connection to engine manifold vacuum. As the edge of the air valve 2S traverses the ports, the lower port 56 is first placed in communication with the manifold vacuum while the port 54 remains above the air valve. Accordingly, at this time the port S4 serves as an air bleed and the transition from the ciosed position in which a pressure not substantially below atmospheric is supplied to the passage 58 to the position in which full manifold vacuum is supplied to the passage, is gradual. Moreover, a second edect is observed when the edge of the valve is in proximity to the ports 54 and 56 and form a restricted passageway for ilow of air around the edge of the valve. At this time a venturi effect is produced which causes a reduction in pressure at the ports 54 and 56.

Extending from the chamber 52 to the interior of the passage 24 is a port 6G in which is movable an elongated valve element 62. The valve element 62 is provided with a recess 63 extending between points d4 and 66 thereon. The distance between the points 6ft and @i6 is somewhat greater than the axial dimension of the port 6l). rlhe arrangement is such that with-the valve 62 in an intermediate position, the recess 63 is located in the port dit and permits flow of air therethrough. Movement of the valve 62 in either direction from the intermediate position results in reduction of the valved area of the port 6i?. In the position illustrated in the ligure the valve 62 is in its extreme right hand position, for a purpose which will subsequently be described, and the port 6ft is accordingly closed. Y

The valve 62 extends through an enlarged opening 72 through the wall of the body Ztl and is connected to a flexible diaphragm 7d. A cover 76 is provided the edges of which clamp the edges of the diaphragm 7d against the edge of a tubular housing portion 7d formed on the exterior of the body 26. There is thus provided a pressure chamber 3? communicating through the opening 72 to the interior of the air passage 24 at a point where manifold vacuum prevails. There is also provided a chamber Se between the diaphragm 74 and cover i6 which is connected by an open port S6 to atmosphere. Disposed in the chamber du is a compression spring 86 urging the valve 62 to the left.

Located in the chamber 84 is a second compression spring 9d one end of which engages the flexible diaphragm '74. Theother end of the spring 90 engages a threaded adjustable spring seat 92 carried by the cover 76. Thus, the effectiveness of the pair of springs 8S and gli may readily be adjusted.

With lthe foregoing construction it is apparent that upon an increase in vacuum within the chamber 42 atmospheric pressure within the chamber 3d is effective to move the diaphragm 32 and hence the control rack l to the left in a direction to decrease the delivery of fuel per revolution of the shaft i2 and thus to lean out the fuel-air ratio. Conversely, a decrease in vacuum within the chamber 42 results in movement of the control rack l to the right, which in turn increases the delivery of fuel by the pump 10 per revolution of its shaft 12, thus increasing the richness of the fuel-air ratio.

The structure as so far described is substantially similar to the system disclosed in applicants above identified prior Patent 2,960,969.

In addition to the fuel regulating system disclosed herein, the present invention comprises fuel shut-off means operable to interrupt delivery of fuel by the pump lil during deceleration of the engine with the air valve 28 closed. Described in general terms, the shut-off valve, which cuts on' supply of fuel to the delivery pump, is moved to closed position by'manifold vacuum and operation of the shut-off valve is controlled by a control valve which in turn is responsive to manifold vacuum. By the use of this control valve it is possible to expose the fuel shut-0E valve to manifold vacuum only during the precise range of vacuum existing during deceleration. This makes it possible to use a very light biasing spring in the fuel shutolf valve.

'ille present arrangement incorporates the additional feature that the fuel shut-olf valve is actuated only during deceleration, whereas prior designs have involved continuous connection of manifold vacuum to the means for actuating the shut-oft" valve. Since manifold vacuum at idle operation approaches the manifold vacuum existing during deceleration, it has been a diflicult problem in prior designs to select a spring effective to shut-off the fuel during deceleration and yet which would not interrupt or restrict the ow of fuel during idle operation.

Referring again to the figure, fuel is supplied to the pump lil from a tank ltl by a pump 102 through a fuel supply passage ldd which contains the shut-olf valve indicated generally vat 106. The shut-off valve includes a port 108 and a headed valve element llt) having a stem 112 extending through a web 114. The valve lt06 includes a main casing 116 and a cap 118 between which are clamped the edges of a flexible diaphragm 126. The diaphragm divides the interior of the housing structure into an atmospheric chamber 122 vented as indicated at =124i, and a vacuum chamber 126 which connects to a vacuum passage 128. Located in the vacuum chamber 126 is a relatively light compression spring 131i effective to maintain the valve element lll) in open position except when the interior of the vacuum chamber ll26V is connected to manifold vacuum.

The vacuum passage 128 terminates in `a port 132 located in the intake passage 24 at a point below the valve 2S. Accordingly, the port 132 is subjected to engine manifold vacuum. Valve structure controlling the application of manifold vacuum to the chamber 126 is included in the vacuum passage 128 and comprises a boss .i3d formed on the air intake body 20 and having a transverse passage 126 intercepting an axially extending passage i3d. The end of the valve element 62 is longitudinally slidable in the passage 13S. Located adjacent the end of the valve element 62 is an annular channel la@ movable into and out of registration with the transverse passage 136. In the figure the valve element 62 is illustrated in its llimiting right hand position to which it will be moved by the exceptionally high manifold vacuum existing in the air passage when the air valve 23 is closed and the engine is decelerated. At this time the registration of the channel 140 and the transverse passage 136 permits the application of manifold vacuum from the port 132 through the vacuum passage 12S to the interior of the vacuum chamber 126. This results in upward movement of the diaphragm as illustrated in the ligure and closure of the valve element 110 against the edge of the valve port 10S. This in turn shuts olf the supply of fuel to the fuel delivery pump 10.

lt will be observed that under any manifold vacuum condition where the manifold vacuum is less than the exceptionally high valuel prevailing during deceleration of the engine with the air valve 28 closed, the annular channel 140 is out of registration with the transverse passage 136 and accordingly, the vacuum chamber 126 is cut off from manifold vacuum. In order to permit opening of the cutoff valve 110 upon closure of the valve constituted by the channel 140, a small bleed port 142 is Provided.

From the foregoing description it will be observed that the regulation of the fuel delivery pump 10 is influenced by manifold vacuum and venturi depression under normal conditions, this regulation being modied when the air valve 28 is closed orwhen exceptionally high or low manifold vacuum conditions are prevailing, all as described in my prior copending application. However, upon attainment of the relatively higher engine manifold vacuum prevailing only when the engine is decelerating with the air valve 28 closed, the supply of fuel to the delivery pump 10 is shut off. When this relatively high manifold vacuum decreases, as it will upon opening of the air valve 28 for example, the shut-olf valve 106 again opens and permits normal automatic regulation of fuel delivery.

The drawing and the foregoing specification constitute a description of the improved fuel supply system in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope Aof which is indicated by the appended claims.

What I claim asmy invention is: ,l 1. A fuel injection system for an internal combustion engine having a manifold, an air intake passage connected to said manifold and a throttle valve in said intake passage, a venturi downstream of said throttle valve, said system comprising a fuel delivery pump connected to supply fuel directly to said engine at a rate dependent on pump delivery, means responsive to manifold vacuum modified by the vacuum at said venturi connected to said pump to regulate its 'delivery rate, a shut-off valve controlling delivery of fuel by said pump, and means responsive to engine deceleration with said throttlevalve closed connected to said shut-off valve.

`2. A fuel injection system for an internal combustion engine having' a'manifold, an air intake passage connected to `said manifold and a throttle valve in said intake passage, a venturi downstream of said throttle valve, said system comprising a -fuel delivery pump connected to supply fuel directly to said engine at a rate dependent on pump delivery, means responsive to manifold vacuum modied' by the vacuum at said venturi connected to said pump to regulate its delivery rate, a shut-olf valve controlling delivery of fuel by said pump, and means responsive to engine manifold vacuum and operable only in response to attainment of a manifold vacuum attained on engine deceleration with closed-air valve to close said shut-off valve.

3.,A fuel injection system for an internal combustion engine having a manifold, an air intake passage connected to said manifold and a throttle valve in said intake passage, a venturi downstream o f said throttle valve, said systmcomprising a fueludelivery pump connected to supply fuel directly to said engine at a rate dependent on pump delivery, means responsive to manifold vacuum modified by the vacuum at said venturi connected to said pump to regulate its delivery rate, a shut-olf valve controlling delivery of fuel by said pump, and means responsive to engine manifold vacuum and operable only in response to attainment of a manifold vacuum in excess of manifold vacuum existing under idle operation of the engine to close said shut-off valve.

4. A fuel injection system for an internal combustion engine having a manifold, an air intake passage connected to said manifold and a throttle valve in said intake passage, a venturi downstream of said throttle valve, said system comprising a fuel delivery pump connected to supply fuel directly to said engine at a rate dependent on pump delivery, means responsive to manifold vacuum modified by the vacuum at said venturi connected to said pump to regulate its delivery rate, a shut-olf valve located at the intake side of said delivery pump controlling delivery of fuel by said pump, and means responsive to engine deceleration with said valve closed connected to said shut-olf valve.

5. A fuel injection system for an internal combustion engine having an air intake passage provided with an air valve, fuel supply means responsive primarily to engine speed for supplying fuel to the engine at a rate dependent primarily on engine speed, vacuum responsive means for modifying the rate of fuel supply comprising means operable during normal engine operation to connect said vacuum responsive means to a source of manifold vacuum, means responsive to air ow to the engine to increase the elfect of manifold vacuum on said vacuum responsive means, means responsive to manifold vacuum for reducing the effect of manifold vacuum on said vacuum responsive means at very high and very low values of manifold vacuum, and fuel shut-olf means responsive to deceleration of the engine operable to shut off fuel supply during engine deceleration.

6. A fuel injection system for an internal combustion engine having an air intake passage provided with an air valve, fuel supply means responsive primarily to engine speed for supplying fuel to the engine at a rate dependent primarily on engine speed, vacuum responsive means for modifying the rate of fuel supply comprising means operable during normal engine operation to connect said vacuum responsive means to a source of manifold vacuum, means responsive to air iiow to the engine to increase the effect of manifold vacuum on said vacuum responsive means, means responsive to manifold Vacuum for reducing the effect of manifold vacuum on said vacuum responsive means at very high and very low values of manifold vacuum, and fuel shut-olf means responsive to engine manifold vacuum and operable to shut olf fuel supply only during the highmanifold vacuum conditions' prevailing during engine deceleration With the air valve closed.

`7. Control means for a fuel pump for delivering fuel directly to an internal combustion engine having an air supply passage having an air valve and a venturi therein comprising a uid actuated pump adjusting motor including a vacuum chamber, a movable pressure responsive element in said chamber connected to said pump, pas-` sage means connecting said chamber, to sources of reduced pressure comprising a port exposed at the inner' surface of said air supply passage at the upstream side of an edge of said air supply valve when closed and in position to be traversed thereby on initial opening movement, a restricted port in the throat of said venturi, a third port in communication with manifold vacuum Within said air supply passage, a regulating valve for restricting said third port when manifold vacuum is outside an intermediate operating range, and fuel shut-olf means associated with said pump responsive to deceleration of the engine operable to shut off fuel supply by said pump to said engine during engine deceleration. 8. Control means for a fuel pump for delivering fuel directly to an internal combustion engine having an air supply passage having an air valve and a venturi therein comprising a fluid actuated pump adjusting motor including a vacuum chamber, a movable pressure responsive element in said chamber connected to said pump, passage means connecting said chamber to sources of reduced pressure comprising a port exposed at the inner surface of said air supply passage at the upstream side of an edge of said air supply valve when closed and in position to be traversed thereby on initial opening movement, a restricted port in the throat of said venturi, a third port in communication with manifold vacuum within said air supply passage, a regulating valve for restricting said third port when manifold vacuum is outside an intermediate operating range, and fuel shut-olf means associated with said pump responsive to engine manifold vacuum and operable to shut off fuel supply by said pump to said engine only during the high manifold vacuum condition prevailing during engine deceleration with the air valve closed.

9. Control means for a fuel pump for delivering fuel directly to an internal combustion engine having an air supply passage having an air valve and a venturi therein comprising a fluid actuated pump adjusting motor including a vacuum chamber, a movable pressure responsive element in said chamber connected to said pump, passage Ymeans connecting said chamber to substantially atmospheric pressure and manifold vacuum during engine idle operation and to a combination of manifold vacuum and venturi depressed manifold vacuum during normal operation, and fuel shut-olf means associated with said pump responsive to deceleration of the engine operable to shut oif fuel supply by said pump to said engine during engine deceleration.

10. Control means for a fuel pump for delivering fuel directly to an internal combustion engine having an air supply passage having an air valve and a venturi therein comprising a fluid actuated pump adjusting motor including a vacuum chamber, a movable pressure responsive element in said chamber connected to said pump, passage means connecting said chamber to substantially atmospheric pressure and manifold vacuum during engine idle operation and to a combination of manifold vacuum and sgoofisai venturiidepressed manifold vacuum during normal operation and fuel shut-off means associated with said pump. responsive to enginemanifold vacuum and operable to shut off fuel supply by said pump to `said engine only during the highmanifold vacuum conditions prevailing during enginedeceleration with the air valve closed.

'11. Afuel injection systemfor an internal combustion engine having a manifold, an a'ir intake passage vconnected to said manifold, a throttle valve in said air intake passage, a venturi in said air intake passage downstream from said throttle valve, said system comprising fuel 'delivery means comprising a pump and operable 'to deliver' fuel directly to `said engine only Vduring delivery of fuel by saidppump, means responsive to manifoldvacuum'modied by the vacuum at said venturi to regulate the rate or" fuel 'delivery to said engine by said pump, a shut-olf valve associated with said fuel delivery means operable when closed to prevent delivery of fuel `by said pump to said engine, and means responsive .to engine deceleration with said throttle valve closed connected to said shut-off valve. T12. A fuel injection system for an internal combustion engine having a manifold, anair intake, passage connected to said manifold, a throttle valve in said air intake passage, a venturi in said air intake-passage downstream from said 'throttle valve, saidsystem .comprising fueldelivery means comprising av pump and operable to deliver fuel directly to said engine only during delivery offuelby `,said pump, means responsive to manifold vacuum modified 'by the vacuum of said venturi to regulate the rate Yof fuel delivery to said. engine by said pump, a shut-olf valve associated with said fuel delivery means controlling the ow of fuel to said pump and operable when closed to prevent delivery ,S Y of fuel by said pump tor said 'engin e,-and means` responsive to engine 'deceleration with said throttle valve-closed connected 'to said shut-oivalve..

.13. AA fuelv injection system vfor anv internal combustion engine 'having a manifold, ,angairintke passage connected to said manifold, a-1throttle valve in said air intake passage, a venturi in said airintake passage downstream-from said throttle Valve, said system comprising fuel delivery means comprisingan enginedriven; pump operable to deliver fuel 4directlyto said engine at a ratepprimarily Vdependent on thespeed `of*l said engine, means responsive tornanifold vacuum modie'dibythe vacuum at said venturi to regulate .the rate of`f uel 'delivery `to said engine by saidjpump,a"shutoif valveassociated withV said fuel deliverymeansoperable'when closed to prevent delivery of fuel by said` pump to said engine, and means responsive to engine deceleration with saidthrottle valve closed connected to; said shut-olf valve.

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